function  guid()  {    
    return  'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g,  function(c)  {     
        var  r  =  Math.random() * 16 | 0,
            v  =  c  ==  'x'  ?  r  :  (r & 0x3 | 0x8);        
        return  v.toString(16);    
    });
}

var uid1 = guid()
var uid2 = guid()
console.log("uid1:" + uid1)
console.log("uid2:" + uid2)


var UUID = require('uuid-js');


// Generate a V4 UUID
var uuid4 = UUID.create();
console.log("x:" + uuid4)